Justification:
Although two of the three known subpopulations of G. desperatus have been extirpated in the last century, one population is known to still exist at Bitter Lake National Wildlife Refuge, New Mexico, USA. While this population is currently stable under present management regimes, habitat loss and deterioration still threaten the survival of the species. Regional groundwater pumping and oil/gas industry operations are ongoing in the Pecos River Valley. The encroachment of residential development in the area also increases the potential risk of groundwater contamination from domestic sewage.

Two subpopulations became extinct during the twentieth century (one in the 1950s, the other in the 1980s). The remaining population exists in Bitter Lake National Wildlife Refuge where current management practices are maintaining population stability.

Gammarid amphipods are generally found in small streams, ponds and springs where the freshwater habitat is cool and well-oxygenated. They are light sensitive and are most active at night. Diet includes algae and submergent vegetation and detritus with juveniles feeding mainly on microbial foods.

Gammarid amphipods are particularly sensitive to changes to their environment caused by pollutant contamination. Regional groundwater pumping and oil/gas industry operations are ongoing in the Pecos River Valley and such activities are known to deplete groundwater aquifers and to contaminate ground- and surface-waters. Residential development within aquifer recharge-discharge areas along the western bounds of Bitter Lake National Wildlife Refuge also bring the threat of further contamination through domestic sewage. Natural events such as prolonged drought may also threaten the extant population by reducing water levels and increasing salinity and contaminant concentrations.